A radio communications apparatus comprises an antenna element for transmitting and/or receiving radio signals. It may also comprise a metal part, separate to the antenna element, that is provided for a function unconnected with the operation of the antenna element. The metal part may be, for example, an electromagnetic shield for shielding of electronic components, a structural support element such as a chassis or frame, part of an integrated component such as battery cell etc.
The presence of the metal part may affect the operational characteristics of the antenna element because of electro-magnetic coupling.
One approach to this problem is to electrically isolate the metal part to suppress electric currents flowing within the part. A disadvantage of this approach is that the metal part may become electro-statically charged.
Another approach to this problem is to ground the metal part.